Jet pump



INVENTOR ATTORNEYS BENJAMIN CLARK BOEC'KELER yMarch 24,l 1953 B. c. BoEcKELER JET PUMP Filed Nov. 19. 1949 "Patented Mar. 24, 1953 JET PUMP Benjamin Clark Boeckeler, Trenton, Mich., as-

signor to The` Hydrojet Corporation, Trenton, Mich., a corporation of Delaware ApplicationNovember 19, 1949, Serial No. 128,265

1 Claim.

This invention relates to pumps of the type known as jet pumps with liquid drive or as liquidjet gas pumps, hereinafter called jet pumps, and has for its object the provision of an improved jet pump capable of exceptional operating eiiiciencies'. My invention is based upon my discovery of a critical shaping of the liquid passageway or ductresulting in a spreading of the liquid jet at Ithe low pressure zone of the duct. This spreading not only results in the attainment of very low pressures but in the pumping of exceptionally large gas volumes in terms of the volume of liquid passing through the duct.

In accordance with my invention, I construct the jet pump with a liquid passageway or duct having a particularly shaped interior comprising a plurality of connected or adjacent chambers. The inlet end which receives the operating liquid leads into a nozzle for directing a stream or jet of liquid into an adjacent enlarged chamber. Following the enlarged chamber in the direction of liquid travel is a restricted chamber, the cross-sectional area of which bears a critical relation to the cross-sectional area of the nozzle. The interior Wall surface of the restricted chamber is a device which I refer to herein as af spreaderf Following :the restricted chamber is a mixing or suction chamber which is preferably of larger cross-sectional area than the enlarged chamber and from which the liquid and gas are discharged. The mixing chamber has a gas inlet in the low pressure zone which lies between the restricted chamber and the place where the diverging liquid contacts the walls of the mixing chamber. The various chambers are preferably cylindrical in cross-section and embrace a common longitudinal axis which may be straight or curved at the discharge end portion. In short, the jet jump comprises a duct internally shaped to provide the interconnected chambers. Liquid from the nozzle passes through the enlarged chamber and therestricted chamber and is spread or pulled apart upon leaving the restricted chamber to an extent where it contacts the wall of the mixing chamber just beyond the gas inlet.

As a result `of extensive experimentation, I have confirmed my conception of a critical relationship in the diameters of the nozzle and the spreader. I have found that a stream or jet of liquid passing through my jet pump undergoes such an expansion on entering the mixing chamber that it lls the chamber creating a very low vacuum. Moreover there is such a volume of voids in the expanded or dispersedliquid that it entrains an exceptionally large amount of gas Fig. 1 is a longitudinalV sectional view of a jet pump of my invention, and;

Fig. 2` illustrates the dimensions of parts of the jet pump of Fig. 1.

The met-al structure or body I has a longitudinal axis 2 in the` center of the passageway` or duct 3 which passes completely through the device. The entrance chamber l includes a cylindrical nozzle 5 adjacent the enlarged chamber 6.

The restricted chamber 1 is between the enlargedl chamber and the mixing chamber 8. While the enlarged chamber and the mixing chamber may be the same or approximately the same diameter, I prefer to use a mixing chamber which is a little larger in diameter than the enlarged chamber. The restricted chamber 1 formed by the annular constriction '9 opens directly into the mixing chamber. The constriction 9 which forms the interior Wall of the expansion chamber serves as a liquid spreader. It may be constructed in the form of a ring inserted into the bore of the enlarged chamber to a point just beyond the gas inlet l0. The flow of the liquid through the duct 3 is merely illustrative of what may take place. The spreader and related parts cause such a spreading or dispersion of the liquid that it entrains relatively large volumes of gas compared to the volume of liquid and results in the creation of a relatively low pressure. For example, in using water at 72 F. under a gage pressure of 56 p. s. i., it produced a shut-off vacuum of 25.4 mmfof mercury absolute pressure. Experimental tests indicate that I can pull a vacuum down to an absolute pressure lower than the vapor pressure'of the propelling liquid. Using water at F. and 100 p. s. i. gage pressure, the jet pump produced an absolute pressure of 113 mm. The vapor pressure of water at 135 F. is 128 mm.

With reference to Fig. 2, a typical jet pump for use with a liquid such as water would have the following dimensions in inches: C=0.349, D=0.151, rf-0.250, F=0.156, G=0.296 and H=0.162. The throat portion I was 8.8 inches long. For this jet pump a1 was 0 35 min. and i was 0 24 min.

The inner maximum diameter H and minimum diameter H of the spreader 9 are so dimensioned with respect to diameter F that a1 is not greater than 6, i is not greater than 4, a2 is not greater than 4, and z is not greater than 3. The ratio of diameter E to diameter F in satisfactory jet pumps has varied from 1.6 to 2.2; however, this ratio may be greater but should not exceed 4.

It Will be apparent With reference to Fig. 2 that the lines a and b extended from the inner front edge of nozzle F' to the near edge of the restricted chamber form angles a1 and a2 with the cylindrical line c of the nozzle which define the maximum and minimum diameters of the restricted chamber respectively and that lines a and b from the same point to the far edge of the restricted chamber form angles l and pz with the cylindrical line c of the nozzle which define the maximum and minimum diameters of the restricted chamber with reference to the far edge and in this manner also establish the length in the axial direction of the restricted chamber.

In the drawings, the duct 3 is shown as embracing a longitudinal .axis in a straight line. The discharge portion of the throat may also be in the form of a curve and the claim is intended to cover both forms.

I claim:

An improved jet pump having a passageway therethrough for the ow of liquid comprising several cylindrical chambers embracing a common longitudinal axis, namely, a nozzle, an enlarged chamber, a restricted chamber and a mixing chamber all connected together in series and in the order named, the enlarged chamber being larger in diameter than the nozzle and restricted chamber, the ratio of the diameter of the restricted chamber to the diameter of the nozzle varying from 1.6 to 4, the angles dened by extending lines from the inner circumference of the nozzle where it joins the enlarged chamber to the near edge of the restricted chamber varying from plus 6 to minus 4 for the maximum and minimum diameters of the restricted chamber respectively, the angles defined by extending the same lines to the far edge of the restricted chamber varying from plus 4 to minus 3 respectively, the mixing chamber having a low -pressure zone adjacent the restricted chamber, and a gas inlet entering the low pressure zone, whereby the lquid jet from the nozzle passes through the enlarged chamber and contacts the wall of the restricted chamber land then expands on entering the mixing chamber resulting in the attainment of low gas pressures and the pumping of as much as 2.2 volumes of gas to one volume of the flowing liquid.

BENJAMIN CLARK BOECKELER.

REFERENCES CITED FOREIGN PATENTS Country Date Great Britain 1911 Number 

